Techniques are disclosed for customization of fin-based transistor devices to provide a diverse range of channel configurations and/or material systems, and within the same integrated circuit die. In accordance with an embodiment, sacrificial fins are cladded and then removed thereby leaving the cladding layer as a pair of standalone fins. Once the sacrificial fin areas are filled back in with a suitable insulator, the resulting structure is fin-on-insulator. The new fins can be configured with any materials by using such a cladding-on-core approach. The resulting fin-on-insulator structure is favorable, for instance, for good gate control while eliminating or otherwise reducing sub-channel source-to-drain (or drain-to-source) leakage current. In addition, parasitic capacitance from channel-to-substrate is significantly reduced. The sacrificial fins can be thought of as cores and can be implemented, for example, with material native to the substrate or a replacement material that enables low-defect exotic cladding materials combinations.